Photostabilization of Polymers: Priciples and ApplicationJ.F. Rabek During the last two decades, the production of polymers and plastics has been increasing rapidly. In spite of developing new polymers and polymeric materials, only 40-60 are used commercially on a large scale. It has been estimated that half of the annual production of polymers is employed outdoors. Increasing the stability of polymers and plastics towards heat, light, atmospheric oxygen and other environmental agents and weathering conditions has always been a very important problem. The photochemical instability of most of polymers limits them to outdoor application, where they are photo degraded fast over periods ranging from months to a few years. To the despair of technologists and consumers alike, photodegrada tion and environmental ageing of polymers occur much faster than can be expected from knowledge collected in laboratories. In many cases, improved methods of preparation and purification of both monomers and polymers yield products of better quality and higher resistance to heat and light. However, without stabilization of polymers by applica tion of antioxidants (to decrease thermal oxidative degradation) and photostabilizers (to decrease photo-oxidative degradation) it would be impossible to employ polymers and plastics in everyday use. |
Contents
1 | |
19 | |
Introduction to the Oxidative and Photo | 42 |
2 | 79 |
Pigments | 167 |
Photostabilizers | 201 |
Hindered Amine Light Stabilizers HALS | 279 |
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Absorbance absorption acetate acid additives Al-Malaika Amer anatase and/or antioxidants Appl Applied Science Publishers benzophenone carbon black carbonyl carbonyl groups Carbonyl index CH₂ CH3 CH3 CH3 CH3 N CH3 chain chelates Chem Chemical chromophoric Ciba-Geigy coatings compounds concentration crystalline Cyanamid Cyanox Cyasorb UV decrease Degrad effect embrittlement EPDM free radicals Goodrite HALS hindered amine hydroperoxide Irganox kinetics LDPE light stabilizers low-density polyethylene LDPE mechanism metal molecular weight molecules monomers nickel(II nitroxy radicals Nondiscolouring nonstaining O₂ OH OH permission from Ref peroxy radicals phosphite photo-oxidation Photochem photodegradation photostabilizers pigments piperidine plastics poly(vinyl chloride polyethylene polymer polymer film polymer matrix polymeric polyolefins polypropylene polypropylene films polystyrene polyurethane powder processing quencher quenching R₁ R₂ react reaction ROOH rubber rutile sample Scott singlet oxygen solubility spectra spectroscopy structure surface synergistic Table temperature thermal oxidation Tinuvin 770 TiO2 Topanol UV irradiation